Systems by which tunnels comprised of segments or panels are rendered water-resistant and air-resistant are known in the art. Several prior art methods for lining tunnels include the use of grooved members or brackets to guide tunnel segments in place combined with the use of packing material between individual tunnel segments. Other tunnel lining methods include attempts to heat seal the cavities between panels in a tunnel cavity in combination with spot tacking of vinyl sheeting on individual panels once the panels are installed in the tunnel cavity. While these methods are somewhat effective in rendering tunnels water-resistant, they are ineffective at rendering a tunnel watertight and airtight. Packing alone is not effective in that the packing is not generally airtight. Spot tacking of sheeting cannot provide an airtight or a sufficiently watertight barrier.
The barrier system of the present invention substantially renders both the panels and the cavities between the panels within a tunnel watertight and airtight thereby overcoming the disadvantages of the prior art. In addition, the panels may be rendered watertight prior to transportation to the tunnel construction site overcoming previous installation limitations and disadvantages as above-described.
It has been discovered that by affixing impermeable membranes to individual panels in a tunnel cavity; positioning filling material within the cavities between the panels in the tunnel cavity; and affixing additional impermeable membranes in facing engagement with the panel membranes such that the additional membranes extend from one panel membrane to an adjacent panel membrane and across the cavity between the adjacent panels, a tunnel barrier system is created which renders the panels and cavities between panels in a tunnel substantially watertight and airtight. Most tunnel cavities are generally pressurized by air. By providing a barrier which is airtight as well as watertight, the present invention substantially decreases the amount of air required to pressurize a tunnel cavity thereby reducing energy and other related costs associated with pressurizing a tunnel cavity.